Apparatus for selectively sampling fluids

ABSTRACT

A selective fluid-sampling apparatus for use in connection with fluid analyzers, which apparatus operates without mixing or contamination of one sample by another. In this apparatus each sample conduit is connected directly and in parallel to a sampling valve and all sampling valves are series-connected to one another by means of a pipe which supplies a carrier gas.

Unite States Patent 1191 Sato Aug. 6, 1.974

[ APPARATUS FOR SELECTIVELY 3,1 l6,642 l/1964 Weir 73/422 0c SAMPLING FLUIDS 3,120,749 2/1964 Paglis et al.... 73/23.] 3,447,360 6/1969 Lasiter 73/23.l [75] Inventor: Atsushi Sato, Yokohama, Japan 3,489,011 1/1970 Firman 73/422 GC [73] Assignee: Nippon Petrochemicals Co., Ltd.,

Tokyo, Japan Primary ExaminerS. Clement Swisher [22] Filed: Feb. 22, 1972 211 Appl. No.: 227,868 [57] ABSTRACT A selective fluid-sampling apparatus for use in con- 52 us. (:1 73/422 GC "fiction with fluid ahhiyzeis which apparatus Operates [51] Int. Cl. G01n 1/22 Without mixing contamination" of one Sample by 158 Field of Search 73/422 oc 23.1 Oihei' hi this apparatus each ShihPih conduit is nected directly and in parallel to a sampling valve and [56] References Cited all sampling valves are series-connected to one an- UNITED STATES PATENTS other by means of a pipe which supplies a carrier gas.

2,757,541 8/1956 Harvey 73/422 GC 2 Claims, 6 Drawing Figures PAIENIE AUG elm SHEEI 1 BF 2 l PRIOR ART Q 3 2 3 5 D FIG.

FIG. 2 PRIOR ART FIG. 3 PRIOR ART APPARATUS FOR SELECTIVELY SAMPLING FLUIDS FIELD OF THE INVENTION This invention relates to a selective fluid-sampling apparatus for use in connection with means for analyzing a plurality of fluid samples, such as a gas chromatographer and, more particularly, to an apparatus which includes a plurality of sampling valves corresponding to the number of samples to be analyzed, said valves being connected in series to one another by means of a pipe which allows a carrier gas to flow therethrough.

BACKGROUND OF THE INVENTION Heretofore, it has been a conventional practice in multiple-sample analyses to intermittently switch the passage flow of a plurality of samples from one sample to the other for the purpose of effectively utilizing one single analyzing instrument. However, such practice has suffered from shortcomings, i.e., the likelihood of mixing between the different samples and of contamination of one sample by another, as it will be explained in greater detail with reference to some of the accompanying drawings.

SUMMARY OF THE INVENTION According to the present invention, these shortcomings are avoided by providing a novel selective fluidsampling apparatus for use in the quantitative sampling of a variety of samples by means of a single analyzing section.

In this apparatus, a plurality of six way valves is preferably used as sampling valves in place of conventional sample-selecting sections, and the conduits adapted to introduce the various samples therein are arranged in parallel, each conduit being connected to its corresponding sampling valve. Further, the sampling valves are connected in series by means of a pipe to the analyzing section of equivalent means. A medium, or carrier gas, is adapted to be introduced through said pipe to purge any remaining sample from the respective sampling valve and from the passage leading to said analyzing section.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are schematic views showing one embodiment of a sample-selecting system of the prior art;

FIG. 3 is a schematic representation of a conventional gas chromatographic apparatus in conjunction with a prior art sample selecting mechanism of improved design;

FIG. 4 is a schematic representation of a gas chromatographic apparatus in conjunction with the sampling apparatus of the present invention;

FIG. 5 is a schematic diagram of a six way valve as used in the sampling apparatus of the present invention; and

FIG. 6 is a schematic diagram of another six way valve as used in the sampling apparatus of the present invention.

DETAILED DESCRIPTION OF THE PRIOR ART AND OF THE INVENTION Any conventional sample selecting apparatus utilizes a flow passage switching mechanism. The system is more specifically illustrated in FIGS. l and 2. As shown in FIG. 1, valve 1 is first closed, valve 2 is then opened and sample a is introduced through conduit 3 into an analyzing instrument 5. Then, valve 2 is closed, valve 1 is opened and sample b is introduced through pipe 4 to the same analyzing instrument. With this arrangement, however, there is a possibility of mixing occurring between sample b and a portion of sample a remaining in the sump section 3' of conduit 3. It follows that sample I) should be introduced to the analyzing instrument after sample a has been completely purged from the sump section by allowing a considerable time to accomplish the above purging operation. In addition to this, if there is a great difference in composition between samples a and b, (for instance), if the concentration of component x is percent in sample a but only a few ppm in sample b, it would take even longer before complete purging is achieved. As it is apparent from FIG. 2, a plurality of samples a, b, c is preselected in a sample selecting section 6 before introducing the sample to the analyzing section 5 of the analyzing instrument. Then, the selected sample is introduced to the analyzing section 5 through a pipe 7 which connects the analyzing section 5 with. the sample selecting section 6. This pipe 7 is used in common for the passage of all of the samples, so that, when switching occurs from one conduit to another, mixing of the samples cannot be avoided, because such a system does not permit the complete removal of one sample from the pipe 7 before the introduction of another, different sample therein, such a pipe 7 being commonly used by all of the samples.

An improved conventional device is shown in FIG. 3, where it can be readily seen that the apparatus includes conduits 8, 9, 10 through which the samples are separately introduced and which are connected to a selecting section 6, which in turn is connected via pipe 7 to a sampling valve 13 containing a metering chamber 12 of a given internal volume. The flow meter is filled with the sample to be analyzed, after which it is isolated, and then swept with a carrier gas from pipe 14- into the separating column 15 and thence to a detecting device 16. Accordingly, the sample which has been selected at the selecting section 6 has to pass through a common passage 7, resulting in the mixing and contaminating of one sample with another, as discussed previously.

According to the present invention, these shortcomings are overcome by providing a. fluid-sampling apparatus which has the capability of selecting with impunity from a plurality of samples. Specifically, the conduits through which each of the samples is introduced, are respectively provided with a sampling valve adapted to effect the quantitative sampling and to be independently actuated. The absence of a common pipe which has been heretofore commonly used for a plurality of samples, eliminates the possiblity of mixing and contamination such as it has been experienced in prior art devices. Furthermore, the present invention does not require long purging periods before switching from one sample to the other. The reason is that the pipe through which a sample is introduced is maintained filled with a carrier gas which flows there through, so that immediately after the sample to be analyzed has travelled through the pipe, assisted by the carrier gas, the pipe is filled only with fresh carrier gas and is automatically completely purged.

Accordingly, when the apparatus of the present invention is applied to an analyzing apparatus, such as a gas chromatographic apparatus, a variety of samples can be analyzed without loss of time by means of a single gas chromatographic apparatus, while providing analytical results of excellent reproducibility.

To further clarify the apparatus of the invention, reference is made now to FIG. 4. In this apparatus, a six way valve is preferably used as the sampling valve 13 in place of the sample selecting section 6 of the prior art. Pipes 8' and 9, adapted for introducing samples a, b (only two are shown) to valve 13 are arranged in parallel and sampling valve 13 is connected in series by means of pipe 14 to sampling valve 13. A carrier gas is made to flow through connecting pipe 14. The sampling valves may be slide valves, or diaphragm valves, or of any other suitable type. FIG. 4 shows an example, wherein the conduits of two different samples a and b are intermittently switched from one to the other before analysis. As illustrated, sample a is shown as being fed into the metering chamber 12 located inside the sampling valve 13, while sample 12 is shown as being fed, through pipe 14 connected to the flow meter, to the separating column 15 and then to the detecting device 16.

To introduce sample a into the gas chromatographic apparatus, the operational modes are reversed, i.e., sampling valve 13' is actuated so as to provide the operational mode of sampling valve 13, and sampling valve 13 is actuated so as to provide the operational mode of sampling valve 13'. In case that a plurality of samples is to be analyzed, the sampling valves, except for the sampling valve of the sample to be analyzed, are all actuated so as to provide the operational mode of valve 13, as shown in FIG. 4, while only the sampling valve through which the sample to be analyzed is flowing is actuated so as to provide the operational mode of valve 13'.

Referring to FIG. 5, where a six way valve is used as a sampling valve, the first port 17 and the second port 18 are connected to pipe 14, the third port 19 and the fourth port 20 are respectively connected to the ends of the metering chamber 12, the fifth port 21 is connected to a vent, and the sixth port 22 is connected to the conduit 8 through which the sample is introduced. In the event that the sample is not introduced to the gas chromatographic apparatus, the first port 17 is connected to the second port 18, the third port 19 to the sixth port 22 and the fourth port 20 to the fifth port 21, as shown by the solid line. On the other hand, when the sample is introudced to the gas chromatographic apparatus, the first port 17 is connected to the fourth port 20, the second port 18 to the third port 19, the sixth port 22 to the fifth port 21, as shown in phantom. Thus, the metering chamber may be first filled with the gas to be analyzed, then isolated, and finally swept with carrier gas into the gas chromatographic apparatus. FIG. 6 illustrates another example of a six way valve in which each portion encircled by phantom lines shows a structurally shallow recess in the upper half of the apparatus body. In this instance, the upper half of the body may be rotated 60 to switch the flow passages from one portion to the other.

As it is apparent from the foregoing, the sampling apparatus of the present invention eliminates any possibility of contamination by previously analyzed samples, because the sampling conduits 8, 9' are connected to independent sampling valves 13. With this arrangement, even if samples a and b are considerably different in the concentration of the gas to be analyzed, there will be no possibility of sample b to become contaminated by sample a before analysis.

Thus, according to the sampling apparatus of the present invention wherein the sampling valves are arranged in parallel with the sample conduits and are connected in series to each other by means of a pipe through which a carrier gas flows, there is no possibility of mixing one sample with another and, furthermore, there is no need to provide for a sample-selecting section as heretofore. The apparatus of the present invention also permits the rapid switching from one sample to the other as well as the analysis of a plurality of samples by means of a single analyzing apparatus.

What is claimed and is wished to secure by Letters Patent of the United States is:

1. Apparatus for selectively sampling fluids from a plurality of fluid samples, said apparatus comprising:

a. a plurality of independent conduits, each said conduit being in fluid flow communication with one of the different fluid samples;

b. a plurality of multi-ported sampling valves connected to said sampling conduits, the number of the sampling valves corresponding to that of samples;

. each of said sampling valves including a pair of inlet and outlet conduits for introducing and discharging a fluid sample, respectively, a pair of inlet and outlet conduits for introducing and discharging a carrier gas, respectively, a metering chamber and a change-over mechanism having two positions for establishing;

i. a first port connection mode therein said sample inlet conduit, said metering chamber and said sample outlet conduit are connected in series while said carrier gas inlet conduit and said carrier gas outlet conduit are shorted; and

ii. a second port connection mode wherein said carrier gas inlet conduit, metering chamber and carrier gas outlet conduit are connected in series; while the sample inlet conduit and sample outlet conduit are shorted;

(I. said sampling valves being serially connected with each other so that said carrier gas outlet conduits of said preceding sampling valves are connected, respectively, to said carrier gas inlet conduits of said directly succeeding sampling valves; and

e. means adapted to change over one of said sampling valves from said first port connection mode to said second port connection mode for collecting a fluid sample, while maintaining other sampling valves in said first port connection mode until the carrier gas conduits through which said fluid gas sample has been collected are filled with a fresh carrier gas for a subsequent sampling operation.

2. The apparatus of claim 1, wherein said sampling valves are six-way valves.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,827,302 I Dated Augu5L6 1974 Inventor(s) Atsushi 12 It is certified that error appears in the above-identified patent and that saidLetters Patent are hereby corrected as shown below:

On the eover sheet insert [30] Foreign Application Priority Data Japan 46-8017 Feb. 22, 1971 Signed end sealed this 3rd day of December B74.

(SEAL) Attest:

McCOY M. GIBSON JR; I C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM'DC 6O375'P59 U.5 GOVERNMENT PRINTING OFFICE I969 O366-33l,

; FORM po-msouo-ss) 

1. Apparatus for selectively sampling fluids from a plurality of fluid samples, said apparatus comprising: a. a plurality of independent conduits, each said conduit being in fluid flow communication with one of the different fluid samples; b. a pluRality of multi-ported sampling valves connected to said sampling conduits, the number of the sampling valves corresponding to that of samples; c. each of said sampling valves including a pair of inlet and outlet conduits for introducing and discharging a fluid sample, respectively, a pair of inlet and outlet conduits for introducing and discharging a carrier gas, respectively, a metering chamber and a change-over mechanism having two positions for establishing; i. a first port connection mode therein said sample inlet conduit, said metering chamber and said sample outlet conduit are connected in series while said carrier gas inlet conduit and said carrier gas outlet conduit are shorted; and ii. a second port connection mode wherein said carrier gas inlet conduit, metering chamber and carrier gas outlet conduit are connected in series; while the sample inlet conduit and sample outlet conduit are shorted; d. said sampling valves being serially connected with each other so that said carrier gas outlet conduits of said preceding sampling valves are connected, respectively, to said carrier gas inlet conduits of said directly succeeding sampling valves; and e. means adapted to change over one of said sampling valves from said first port connection mode to said second port connection mode for collecting a fluid sample, while maintaining other sampling valves in said first port connection mode until the carrier gas conduits through which said fluid gas sample has been collected are filled with a fresh carrier gas for a subsequent sampling operation.
 2. The apparatus of claim 1, wherein said sampling valves are six-way valves. 